#include <stdio.h>
#include <assert.h>
char* my_strcpy(char* dest,const char* src)
{
	char* ret = dest;
	assert(*dest && *src);
	while (*dest++ = *src++);
	return ret;
}
int main()
{
	char str1[] = "abcdef";
	char str2[20] = "abcd";
	printf("%s\n", my_strcpy(str2,str1));
}